Such fuselage landing gears are known in which the leg is constituted by an upside-down L-shaped rigid strut, with a wheel lever hinged to the bottom end thereof, extending rearwards, and carrying a single wheel, or more commonly a pair of side-by-side wheels. The rigid strut is hinged to the aircraft structure by a branch that is horizontal or slightly inclined, and a shock absorber connects said branch to the wheel lever.
Under such circumstances, the length of the landing gear is essentially the same in the landing gear retracted position and in the landing gear extended position (before the wheels make contact with the ground): if the hinge axis of the rigid strut is inclined relative to the structure of the aircraft, then the wheel is indeed advanced a little when the landing gear is raised, but the advance remains very small.
It may be advantageous to seek landing gear of a structure enabling it to be long on landing, but short during taxiing and also when in the retracted position, thereby avoiding excessive sideways dimensions of the associated fairing on the aircraft, and possibly also avoiding the need to modify existing frames, thereby making it possible to provide aircraft that have been modified to accept greater loads, and consequently needing to be fitted with tires of larger dimensions, while still retaining the same fuselage structure.
Unfortunately, landing gear fitted with apparatus for shortening the leg thereof while it is being raised are generally complex and bulky in structure.
The state of the art may be rounded off by mentioning documents EP-A-0 031 601 and FR-A-1 245 515, which show solutions implemented in three portions, with a horizontal portion hinged to the structure of the airplane, a vertical portion hinged to said horizontal portion, and a structural bar to brace the vertical portion (said bar also serving as a guide bar while the landing gear is being raised).